1. Field of the Invention
This invention relates to a mixing apparatus suitable, for example, as a container for a medical solution in drip infusion. The mixing apparatus is useful in the field of medical treatment.
2. Description of the Related Art
To administer a powdered drug or lyophilized drug such as an antibiotic or an anticarcinostatic substance to a patient at a medical institution such as a hospital, it has heretofore been the practice to dissolve the drug, which is stored in a container such as a vial, and then to administer the resulting medical solution by drip infusion. In this case, the container with the drug stored therein and a container, in which a dissolving solution for the drug is stored, are connected together by a connecting device such as a double-ended needle or a tubular connector, whereby the dissolving solution is transferred to the former container to dissolve the drug. This handling is however cumbersome and time-consuming and, moreover, the formation of a connecting hole through the drug container may permit the entry of outside air, resulting in the potential danger that the drug inside the drug container could be contaminated.
With a view toward eliminating the above problems, i.e., the cumbersome mixing procedure and the potential danger of contamination, attempts have therefore been made to provide a single-piece apparatus formed in combination of a drug container and a dissolving solution container. Containers for a medical solution have been proposed accordingly, including that disclosed in Japanese Language Laid-Open Publication (PCT) No. 501129/1986 (International Publication No. WO 85/03432) in which a capsule with a vial as a drug container stored therein and a flexible container having a solution outlet and containing a dissolving solution therein are connected together by a tube. Provided inside the tube are a hollow spike needle on a side of the vial and a breakable member on a side of the flexible container. The breakable member blocks a passage in the tube so that the dissolving solution is prevented from flowing through the tube.
Upon administration, the vial inside the capsule is pushed down to have the spike needle penetrate through a rubber plug of the vial, so that the flexible container and the vial are connected together first of all. The breakable member in the tube is then broken by hand so that the passage in the tube is communicated to mix the dissolving solution with the drug.
Although the medical solution container disclosed in Japanese Language Laid-Open Publication (PCT) No. 501129/1986 is improved in the potential danger of contamination from the outside upon communication of the drug container with the flexible container, the latter container being filled with the dissolving solution, to mix the dissolving solution with the drug, the vial itself is caused to slide in the drug container upon the communication so that the surface of the vial has to slide over a large area. Maintenance of high-level tightness is therefore not very easy structurally. Further, the passage must be opened by breaking the breakable member to open the passage after piercing the rubber plug of the vial with the spike needle. Substantial labor is therefore still required. If the breakable member is broken incomplete, the solution has difficulty in flowing through the passage, resulting in the problem that substantial time may be required for the dissolution.
Medical solution containers such as that disclosed in Japanese Patent Laid-Open No. 1277/1990 have also been proposed as further improvements. This medical solution container comprises a flexible container containing a dissolving solution or a diluting solution therein and having a closure-equipped liquid passage portion at an uppermost end thereof, a capsule connected to the flexible container, a drug container held in the capsule and having a mouth portion hermetically sealed with a pierceable plug, and a communication means for communicating the interior of the flexible container with the interior of the drug container. The communication means in turn comprises a hollow spike needle, which has a hub at an intermediate point thereof and bevels at opposite ends thereof, and a brake means for controlling the sequence of communication such that the closure of the flexible container is pierced by one of the bevels of the spike needle after the plug of the drug container has been pieced by the other bevel of the spike needle.
Although the medical solution container disclosed in Japanese Patent Laid-Open No. 1277/1990 offers a reduction in the potential danger of contamination upon communication of the drug container with the flexible container, the latter container being filled with the dissolving solution, to mix the dissolving solution with the drug and also in the laborious handling required upon the communication and mixing, sliding of the drug container itself is required upon the communication as in Japanese Language Laid-Open Publication (PCT) No. 501129/1986 referred to above so that it is structurally difficult to achieve complete tightness. The communication means requires a hollow spike needle, which has a hub at an intermediate point thereof and bevels at opposite ends thereof, and a complex structure for controlling the sequence of communication, e.g., the closure of the flexible container is pierced by one of the bevels of the spike needle after the plug of the drug container has been pierced by the other bevel of the spike needle. The medical solution container therefore requires a greater number of parts, leading to the problems that its production cost is high and the rate of occurrence of handling troubles is high.